Tough question,the ones I've narrowed it down to are BMC,JR or K & N,the BMC is apparantley used by Ferrari,not sure if thats a good or a bad recommendation ! JR tend to be used by Japanese
Rally/sports cars and K & N are everywhere.
Im initially tempted by the BMC,mainly cause Id never heard of them before and Ive had K & N on other cars,
The other thing you shoukd then consider is Intakes systems !